Glomerular Disease Mechanisms mediated by Podocyte TRPC6

足细胞 TRPC6 介导的肾小球疾病机制

基本信息

批准号：
8723165
负责人：
Jochen Reiser
金额：
$ 30.75万
依托单位：
RUSH UNIVERSITY MEDICAL CENTER
依托单位国家：
美国
项目类别：
财政年份：
2010
资助国家：
美国
起止时间：
2010-08-10 至 2015-07-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8723165
关键词：
Actins Address Affect Applications Grants Binding Biochemical Biological Preservation Calcineurin Calcineurin Pathway Cathepsin L Cell membrane Cyclic AMP-Dependent Protein Kinases Cytoskeleton Data Development Disease Dominant-Negative Mutation Elements Enzymes F-Actin Feedback Focal Segmental Glomerulosclerosis Foot Process Forskolin Genes Goals Human Hyperactive behavior Inherited Injury Ion Channel Kidney Kidney Diseases Kidney Failure Knock-out Lead Lesion Mediating Membrane Modeling Molecular Biology Mus Mutate Mutation Nephrotic Syndrome Pathway interactions Patients Permeability Pharmaceutical Preparations Phenotype Phosphorylation Physiological Play Protein Dephosphorylation Proteins Proteinuria Regulation Renal glomerular disease Resistance Rodent Role Signal Transduction Small Interfering RNA System Testing Work calcineurin phosphatase calmodulin-dependent protein kinase II gain of function mutation in vivo mutant novel overexpression podocyte public health relevance response slit diaphragm synaptopodin

项目摘要

DESCRIPTION (provided by applicant): This project aims to delineate disease causing mechanisms of dysfunctional ion channel TRPC6 in podocytes. TRPC6 is part of the slit diaphragm relating Ca2+ signals into podocyte foot processes and mutated TRPC6 or induced expression of wild type TRPC6 protein can cause hereditary and acquired proteinuric diseases, respectively. Thus, (dys-) regulation of TRPC6 likely affects millions of patients with glomerular disease. We have generated novel preliminary data demonstrating a unique functional interaction between TRPC6 and synaptopodin producing a regulatory loop, that coordinates physiological podocyte function but triggers podocyte injury in the case of dysregulated TRPC6 mediated Ca2+ signals. We propose to test our central hypothesis that TRPC6 and synaptopodin cooperate in the regulation of the dynamic podocyte actin cytoskeleton. While synaptopodin binds to TRPC6 and regulates its membrane expression, TRPC6 mediated Ca2+ influx determines the stability of synaptopodin through Ca2+ sensitive enzymes calcineurin and protein kinase A (PKA). According to our novel data, increased TRPC6 channel activity disrupts normal podocyte actin cytoskeletal dynamics via the activation of calcineurin that in turn leads to the degradation of synaptopodin thereby causing proteinuric kidney disease. In addition, diminished TRPC6 mediated Ca2+ influx into podocytes leads to reduced activity of PKA and thus reduced protective synaptopodin phosphorylation with its subsequent degradation. Normal Ca2+ transport of TRPC6 maintains physiological synaptopodin levels that allow a dynamic regulation of the podocyte foot process system and kidney barrier. Specific Aim 1 will address how TRPC6 regulates synaptopodin-mediated actin cytoskeletal dynamics. Specific Aim 2 seeks to define how synaptopodin affects TRPC6 channel activity and localization. In Specific Aim 3, we will study the consequences of TRPC6 deficiency and TRPC6 hyperactivity on podocyte actin cytoskeletal dynamics and glomerular barrier function in vivo. Our work will clarify an important downstream mechanism that permits podocyte injury originating from dysregulated TRPC6. Our findings may have broad implications for the understanding of the pathobiology of TRPC6-related human kidney diseases including Focal Segmental Glomerulosclerosis (FSGS) and promote the development of anti-proteinuric drugs interfering with TRPC6 and its cellular effects on podocytes.

描述（由申请人提供）：该项目旨在描述疾病，引起足功能失调的离子通道TRPC6在足细胞中的机制。 TRPC6是将Ca2+信号与足球脚部过程和突变的TRPC6相关的缝隙膜片的一部分，或者诱导的野生型TRPC6蛋白的表达分别会导致遗传性和获得性蛋白尿性疾病。因此，（DYS-）调节TRPC6可能会影响数百万肾小球疾病患者。我们已经生成了新的初步数据，证明了TRPC6与突触蛋白之间产生调节环的独特功能相互作用，从而协调生理足细胞功能，但在TRPC6介导的Ca2+信号失调的情况下，触发了Podocyte损伤。我们建议测试我们的中心假设，即在调节动态podocyte肌动蛋白细胞骨架的调节中TRPC6和突触蛋白合作。突触蛋白与TRPC6结合并调节其膜表达，而TRPC6介导的Ca2+流入确定突触蛋白通过Ca2+敏感酶钙调神经酶和蛋白激酶A（PKA）的稳定性。根据我们的新数据，增加的TRPC6通道活性通过激活钙调神经蛋白的激活而破坏了正常的足细胞肌动蛋白细胞骨架动力学，从而导致突触蛋白的降解，从而导致蛋白尿肾脏疾病。此外，TRPC6介导的Ca2+流入到足细胞中的降低导致PKA活性降低，从而降低了保护性突触蛋白磷酸化，随后降解。 TRPC6的正常CA2+运输维持生理突触素水平，允许对Podocyte脚步过程和肾屏障的动态调节。具体目标1将解决TRPC6如何调节突触蛋白介导的肌动蛋白细胞骨架动力学。特定的目标2试图定义突触量如何影响TRPC6通道活动和定位。在特定的目标3中，我们将研究TRPC6缺乏症和TRPC6多动对体内足细胞肌动蛋白细胞骨架动力学和肾小球屏障功能的后果。我们的工作将阐明一种重要的下游机制，该机制允许源自失调的TRPC6损伤。我们的发现可能对理解与TRPC6相关的人肾脏疾病的病理生物学具有广泛的影响，包括局灶性节段性肾小球硬化症（FSGS），并促进抗蛋白尿药物干扰TRPC6及其细胞对Podocytes的抗蛋白尿药物的发展。